Some of the present inkjet printers in the market require the ink cartridges to be installed and removed by operating the locking covers of the printhead. The locking covers are pivotably mounted to the printhead and include at least one pulling hook. A supporting tab which matches with the pulling hook has to be provided on the front end outside surface of each ink cartridge so that each supporting tab is engaged by a pulling hook when the ink cartridge is being removed. Otherwise, the removal of the ink cartridge will be very inconvenient and sometimes even impossible. When the locking cover is in an open position, the ink cartridge cannot be easily installed in the printhead by pressing directly on the upper surface of the ink cartridge because the supporting tab is engaged with the pulling hook of the locking cover. Instead, to install the ink cartridge the locking cover must be pivoted to the closed position, which in turn presses a leaf spring which is disposed on bottom surface of the locking cover onto the upper surface of the ink cartridge body. Therefore, for an ink cartridge having these exterior installation structures, not only does the installation of the ink cartridge require the locking cover to provide the functions of supporting the ink cartridge and pressing it into proper installed position, but also the removal of the ink cartridge requires the locking cover to pull or lever the ink cartridge out of the printhead as a result of the engagement between the pulling hook and the supporting tab. Furthermore, after the ink cartridge is installed in place, the locking cover is required to protect the ink cartridge against dust and from being accidentally dislodged from the printhead. The installation, removal and use of this type of ink cartridge therefore depends excessively on the functions of the locking cover.
The leaf spring of the locking cover is held in a compression mode for long periods of time. This means that the leaf spring is easily deformed and may even fail due to fatigue. If the leaf spring is deformed or fails then the ink cartridge may not be installed in a proper position in the printhead and the ink cartridge may not be recognized by the printer. The ink cartridge may also provide poor print quality. In addition, the pulling hook of the locking cover is easily deformed or broken making it difficult to remove the ink cartridge.